Audio system having an improved efficiency and extended operation time

Patent metadata

Field	Value
Publication number	US-2017194912-A1
Application number	US-201715465586-A
Country	US
Kind code	A1
Filing date	Mar 21, 2017
Priority date	Jan 2, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

Embodiments of the disclosure may include a method and apparatus for improving the efficiency and extending the operation time between recharges or replacement batteries of a portable audio delivery system. The audio delivery system may include a processor, an audio processing device, a speaker, and a rechargeable power source. The audio delivery system is generally configured to generate and/or receive an audio input signal and efficiently deliver an amplified, high quality audio output signal to a user. In some embodiments of the disclosure, the audio processing device of the audio delivery system may include a switch mode power supply (SMPS), a signal delay element, an envelope detector, and a switching signal amplifier.

First claim

What is claimed is:

1 . An audio device, comprising:
an envelope detector configured to receive an input signal that includes audio signal data distributed over a first time period, and produce a power instruction signal based on at least one characteristic of the input signal detected within the time period; a power supply providing a battery voltage; a switch mode power supply configured to generate a variable rail voltage, wherein the generated variable rail voltage is based on the battery voltage and the power instruction signal received from the envelope detector during the first time period, and the variable rail voltage signal comprises a sum of one or more incremental voltages generated by the switch mode power supply and the output voltage of the battery; and a switching signal amplifier configured to receive the generated variable rail voltage and the input signal, and produce an output signal that is based on the received input signal and a gain of the switching signal amplifier, wherein the output signal comprises a plurality of peak output voltages formed at different times within a second time period, wherein the second time period is shifted in time relative to the first period of time at least an amount equal to a predetermined lag time.

2 . The audio device of claim 1 , further comprising:
a signal delay element configured to receive the input signal and produce a delayed input signal, which includes the audio signal data, after the predetermined lag time has elapsed, and wherein the input signal received by the switching signal amplifier comprises the delayed input signal.

3 . The audio device of claim 2 , wherein the predetermined lag time is in a range from 1 microsecond to 300 milliseconds.

4 . The audio device of claim 2 , wherein the envelope detector comprises a digital signal processor (DSP) module.

5 . The audio device of claim 4 , wherein the signal delay element is a digital signal delay element that is formed within the digital signal processor (DSP) module.

6 . The audio device of claim 4 , wherein the predetermined lag time is equal to or greater than an input signal sampling rate performed by the digital signal processor (DSP) module.

7 . The audio device of claim 1 , wherein the switching signal amplifier comprises a class-D signal amplifier.

8 . The audio device of claim 1 , wherein the envelope detector is further configured to:
detect a plurality of local amplitude peaks associated with the input signal, wherein the plurality of local amplitude peaks comprise a first local amplitude peak and a second local amplitude peak, and the first local amplitude peak occurs before the second local amplitude peak in time, and vary the produced power instruction signal using a decay algorithm when a magnitude of the first local amplitude peak is greater than a magnitude of the second local amplitude peak.

9 . The audio device of claim 8 , wherein the envelope detector is further configured to vary the power instruction signal using a fast attack algorithm when a magnitude of the first local amplitude peak is less than a magnitude of the second local amplitude peak.

10 . The audio device of claim 8 , wherein the varied power instruction signal formed by the decay algorithm comprises an exponential decay.

11 . The audio device of claim 1 , wherein the one or more incremental voltages generated by the switch mode power supply comprises at least two discrete voltage levels.

12 . A method of conserving power in an audio device, comprising:
receiving, by a digital signal processor, an input signal that includes audio signal data distributed over a first time period; generating a power instruction signal, using an envelope detector within the digital signal processor, that is based on at least one characteristic of the received input signal detected within the first time period; delivering, from a switch mode power supply, a variable rail voltage signal to a switching amplifier, wherein the variable rail voltage is derived from an output voltage received from a battery and the power instruction signal, and the delivered variable rail voltage signal comprises a sum of one or more incremental voltages generated by the switch mode power supply and the output voltage of the battery; and generating, with the switching signal amplifier, an output signal having an output voltage based on the input signal and a gain of the switching signal amplifier, wherein the output signal comprises a plurality of peak output voltages formed at different times within a second time period, wherein the second time period is shifted in time relative to the first period of time at least an amount equal to a predetermined lag time.

13 . The method of claim 12 , further comprising:
delaying the input signal provided to the switching signal amplifier the predetermined lag time, wherein the generated output signal is based on the delayed input signal.

14 . The method of claim 13 , wherein the predetermined lag time is in a range from 1 microsecond to 300 milliseconds.

15 . The method of claim 13 , wherein the second time period is shifted in time relative to the first period of time at least an amount equal to the predetermined lag time.

16 . The method of claim 13 , wherein the delayed input signal is performed by a digital signal processor (DSP) module, wherein the predetermined lag time is equal to or greater than an input signal sampling rate performed by the digital signal processor (DSP) module.

17 . The method of claim 12 , wherein the switching signal amplifier comprises a class-D signal amplifier.

18 . The method of claim 12 , further comprises:
detecting a plurality of local amplitude peaks associated with the input signal, wherein the plurality of local amplitude peaks comprise a first local amplitude peak and a second local amplitude peak, and the first local amplitude peak occurs before the second local amplitude peak in time, and adjusting the power instruction signal using a decay algorithm when a magnitude of the first local amplitude peak is greater than a magnitude of the second local amplitude peak.

19 . The method of claim 18 , wherein the adjusted power instruction signal comprises an exponential decay that is generated by the decay algorithm.

Assignees

• Logitech Europe Sa

Inventors

• Olson Alan
• Chiu Sean
• Pan Jianhua
• Mouzakis Constantine
• Anderson Jeffrey
• Nicolet Patrick

Classifications

• H03F2200/102

  A non-specified detector of a signal envelope being used in an amplifying circuit · CPC title

• H03F3/2171

  with field-effect devices (H03F3/2173 - H03F3/2178 take precedence) · CPC title

• H03F1/0227 Primary

  using supply converters · CPC title

• H03F2200/03

  the amplifier being designed for audio applications · CPC title

• H03F2200/435

  A peak detection being used in a signal measuring circuit in a controlling circuit of an amplifier · CPC title